Tire Index

On the sidewall of all tires you will find the Load Index and Speed Rating for that tire. An example of this is the 115S that we will be using in the example below. There is also a couple reference charts included at the bottom to look up any tire load rating or tire speed rating that you are interested in.

Tire Load Ratings For The Chevy Silverado 1500

Understanding what the numbers mean in the Tire Load Ratings like 99T, 115S, and so on.

That 115S tire load rating tells you a lot about the applications for these tires.
A tire with a load index of 115, it can support 2,679 pounds at maximum air pressure. Take that number and multiply it by 4 tires (4 x 2,679 = 10,716 pounds) to get your vehicles maximum load carrying capacity. The S is the speed rating, in this case S = 112mph.

Tire Load Rating Chart

The tires load index is an number ranging from 0 to 279 that corresponds with the load-carrying capacity of a tire. For the light truck tires we will only be looking at the ratings between 0 and 150 in the chart below. This will include tires through 10 ply rating and should cover about all tires used on the Chevrolet Silverado 1500, 2500 and 3500 series pickups.

Light Truck Tires—Ply Ratings are actually an old and outdated designation that has been replaced by the much more descriptive Tire Load Rating. Looking back, a "C" indicates the tire has a 6-ply load carrying capacity. The tire is not actually built with 6 plies, but contains one or two plies of equivalent strength. A "D" is an 8-ply rating, and an "E" is a 10-ply rating. If there is no letter, the tire has a standard 4-ply rating.

Load- Carrying Capacity Index Ratings

Load Index

Load (lbs)

Load Index

Load (lbs)

Load Index

Load (lbs)

0

99

50

419

100

1764

1

102

51

430

101

1819

2

105

52

441

102

1874

3

107

53

454

103

1929

4

110

54

467

104

1984

5

114

55

481

105

2039

6

117

56

494

106

2094

7

120

57

507

107

2149

8

123

58

520

108

2205

9

128

59

536

109

2271

10

132

60

551

110

2337

11

136

61

567

111

2403

12

139

62

584

112

2469

13

143

63

600

113

2535

14

148

64

617

114

2601

15

152

65

639

115

2679

16

157

66

639

116

2756

17

161

67

677

117

2833

18

165

68

694

118

2910

19

171

69

716

119

2998

20

176

70

739

120

3086

21

182

71

761

121

3197

22

187

72

783

122

3307

23

193

73

805

123

3417

24

198

74

827

124

3527

25

204

75

852

125

3638

26

209

76

882

126

3748

27

215

77

908

127

3858

28

220

78

937

128

3968

29

227

79

963

129

4079

30

234

80

992

130

4189

31

240

81

1019

131

4289

32

247

82

1047

132

4409

33

254

83

1074

133

4541

34

260

84

1102

134

4674

35

267

85

1135

135

4806

36

276

86

1168

136

4938

37

282

87

1201

137

5071

38

291

88

1235

138

5203

39

300

89

1279

139

5357

40

309

90

1323

140

5512

41

320

91

1356

141

5677

42

331

92

1389

142

5842

43

342

93

1433

143

6008

44

353

94

1477

144

6173

45

364

95

1521

145

6393

46

375

96

1565

146

6614

47

386

97

1609

147

6779

48

397

98

1653

148

6844

49

408

99

1709

149

7165

150

7385

Tire Speed Rating Chart

The tires speed rating is most commonly associated with the maximum speed a tire can sustain for a certain period of time without risk of tire failure. But this number is about a lot more than just speed. The Tire Speed Rating is also about performance and tells you a lot about just how that tire will perform in various situations. The Tire Speed Rating tells you about how efficient your tires are at getting rid of heat and how well they perform in braking, cornering as well as how well they will grip and swerve on the road.